【Abstract】 Objective To compare the effects of bracketless invisible orthodontics and fixed orthodontics on periodontal health and root resorption of patients. Methods 87 patients with anterior teeth loss repair-assisted orthodontics admitted to department of stomatology of our hospital from January 2015 to December 2015 were selected and divided into observation group and control group. 47 patients in observation group wore loss repair-assisted bracketless invisible aligner while 40 patients in control group wore loss repair-assisted fixed orthodontic straight wire appliances. Periodontal indices, including gingival index (GI) , sulcus probing depth (SPD) , sulcus bleeding index (SBI) , plaque index (PLI) were examined in both groups at three control visits (1st, 3rd, 6th month respective). Then, the impacts of two appliances on the periodontal health and root resorption of the patients were compared and analyzed. Results Before the orthodontic treatment, the periodontal condition of all patients was good with no obvious plaque, and the depth of probing was less than 3 mm, so no difference was found in the periodontal index of the two groups (P〉0.05). Thelevels of AST and ALP in the observation group were significantly better than those in the control group at the post-treatment 6mon(P<0.05). After the orthodontic treatment, periodontal indices of the observation group had increased, the post-treatment GI, SBI and PLI were significant different from those before treatment(P<0.05) , while no difference was found in the SPD (P〉0.05). The periodontal index of the control group increased after treatment, with no significant difference(P〉0.05)( At the post 6mon of orthodontic treatment, the incidence rate of the root resorption was 48. 4% in the observation and was 69.7% in the control group (PV0. 05) , which was increased to 69. 4% in the observation and was 84. 8% in the control group after finishing the orthodontic treatment(P<0.05). No root resorption was more than 3 mm in the two groups at the post 6mon, while root resorption more than 3 mm occurred in the control group at the end of the treatment. Conclusion The application of anterior teeth loss repair-assisted bracketless invisible aligner in the orthodontic treatment has less effect on the periodontal health and oral hygiene, and can reduce the root resorption to some extent.